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* Copyright 2006 The WebRTC Project Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include "webrtc/typedefs.h"
// If you for some reson need to know if DCHECKs are on, test the value of
// RTC_DCHECK_IS_ON. (Test its value, not if it's defined; it'll always be
// defined, to either a true or a false value.)
#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
#define RTC_DCHECK_IS_ON 1
#define RTC_DCHECK_IS_ON 0
#ifdef __cplusplus
extern "C" {
NO_RETURN void rtc_FatalMessage(const char* file, int line, const char* msg);
#ifdef __cplusplus
} // extern "C"
#ifdef __cplusplus
// C++ version.
#include <sstream>
#include <string>
#include "webrtc/rtc_base/safe_compare.h"
// The macros here print a message to stderr and abort under various
// conditions. All will accept additional stream messages. For example:
// RTC_DCHECK_EQ(foo, bar) << "I'm printed when foo != bar.";
// - RTC_CHECK(x) is an assertion that x is always true, and that if it isn't,
// it's better to terminate the process than to continue. During development,
// the reason that it's better to terminate might simply be that the error
// handling code isn't in place yet; in production, the reason might be that
// the author of the code truly believes that x will always be true, but that
// she recognizes that if she is wrong, abrupt and unpleasant process
// termination is still better than carrying on with the assumption violated.
// RTC_CHECK always evaluates its argument, so it's OK for x to have side
// effects.
// - RTC_DCHECK(x) is the same as RTC_CHECK(x)---an assertion that x is always
// true---except that x will only be evaluated in debug builds; in production
// builds, x is simply assumed to be true. This is useful if evaluating x is
// expensive and the expected cost of failing to detect the violated
// assumption is acceptable. You should not handle cases where a production
// build fails to spot a violated condition, even those that would result in
// crashes. If the code needs to cope with the error, make it cope, but don't
// call RTC_DCHECK; if the condition really can't occur, but you'd sleep
// better at night knowing that the process will suicide instead of carrying
// on in case you were wrong, use RTC_CHECK instead of RTC_DCHECK.
// RTC_DCHECK only evaluates its argument in debug builds, so if x has visible
// side effects, you need to write e.g.
// bool w = x; RTC_DCHECK(w);
// - RTC_CHECK_EQ, _NE, _GT, ..., and RTC_DCHECK_EQ, _NE, _GT, ... are
// specialized variants of RTC_CHECK and RTC_DCHECK that print prettier
// messages if the condition doesn't hold. Prefer them to raw RTC_CHECK and
// - FATAL() aborts unconditionally.
// TODO(ajm): Ideally, checks.h would be combined with logging.h, but
// consolidation with system_wrappers/logging.h should happen first.
namespace rtc {
// Helper macro which avoids evaluating the arguments to a stream if
// the condition doesn't hold.
#define RTC_LAZY_STREAM(stream, condition) \
!(condition) ? static_cast<void>(0) : rtc::FatalMessageVoidify() & (stream)
// The actual stream used isn't important. We reference |ignored| in the code
// but don't evaluate it; this is to avoid "unused variable" warnings (we do so
// in a particularly convoluted way with an extra ?: because that appears to be
// the simplest construct that keeps Visual Studio from complaining about
// condition being unused).
#define RTC_EAT_STREAM_PARAMETERS(ignored) \
(true ? true : ((void)(ignored), true)) \
? static_cast<void>(0) \
: rtc::FatalMessageVoidify() & rtc::FatalMessage("", 0).stream()
// Call RTC_EAT_STREAM_PARAMETERS with an argument that fails to compile if
// values of the same types as |a| and |b| can't be compared with the given
// operation, and that would evaluate |a| and |b| if evaluated.
#define RTC_EAT_STREAM_PARAMETERS_OP(op, a, b) \
RTC_EAT_STREAM_PARAMETERS(((void)rtc::Safe##op(a, b)))
// RTC_CHECK dies with a fatal error if condition is not true. It is *not*
// controlled by NDEBUG or anything else, so the check will be executed
// regardless of compilation mode.
// We make sure RTC_CHECK et al. always evaluates their arguments, as
// doing RTC_CHECK(FunctionWithSideEffect()) is a common idiom.
#define RTC_CHECK(condition) \
RTC_LAZY_STREAM(rtc::FatalMessage(__FILE__, __LINE__).stream(), \
!(condition)) \
<< "Check failed: " #condition << std::endl << "# "
// Helper macro for binary operators.
// Don't use this macro directly in your code, use RTC_CHECK_EQ et al below.
// TODO(akalin): Rewrite this so that constructs like if (...)
// RTC_CHECK_EQ(...) else { ... } work properly.
#define RTC_CHECK_OP(name, op, val1, val2) \
if (std::string* _result = \
rtc::Check##name##Impl((val1), (val2), #val1 " " #op " " #val2)) \
rtc::FatalMessage(__FILE__, __LINE__, _result).stream()
// Build the error message string. This is separate from the "Impl"
// function template because it is not performance critical and so can
// be out of line, while the "Impl" code should be inline. Caller
// takes ownership of the returned string.
template<class t1, class t2>
std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
std::ostringstream ss;
ss << names << " (" << v1 << " vs. " << v2 << ")";
std::string* msg = new std::string(ss.str());
return msg;
// MSVC doesn't like complex extern templates and DLLs.
#if !defined(COMPILER_MSVC)
// Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
// in
extern template std::string* MakeCheckOpString<int, int>(
const int&, const int&, const char* names);
extern template
std::string* MakeCheckOpString<unsigned long, unsigned long>(
const unsigned long&, const unsigned long&, const char* names);
extern template
std::string* MakeCheckOpString<unsigned long, unsigned int>(
const unsigned long&, const unsigned int&, const char* names);
extern template
std::string* MakeCheckOpString<unsigned int, unsigned long>(
const unsigned int&, const unsigned long&, const char* names);
extern template
std::string* MakeCheckOpString<std::string, std::string>(
const std::string&, const std::string&, const char* name);
// Helper functions for RTC_CHECK_OP macro.
// The (int, int) specialization works around the issue that the compiler
// will not instantiate the template version of the function on values of
// unnamed enum type - see comment below.
#define DEFINE_RTC_CHECK_OP_IMPL(name) \
template <class t1, class t2> \
inline std::string* Check##name##Impl(const t1& v1, const t2& v2, \
const char* names) { \
if (rtc::Safe##name(v1, v2)) \
return nullptr; \
else \
return rtc::MakeCheckOpString(v1, v2, names); \
} \
inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
if (rtc::Safe##name(v1, v2)) \
return nullptr; \
else \
return rtc::MakeCheckOpString(v1, v2, names); \
#define RTC_CHECK_EQ(val1, val2) RTC_CHECK_OP(Eq, ==, val1, val2)
#define RTC_CHECK_NE(val1, val2) RTC_CHECK_OP(Ne, !=, val1, val2)
#define RTC_CHECK_LE(val1, val2) RTC_CHECK_OP(Le, <=, val1, val2)
#define RTC_CHECK_LT(val1, val2) RTC_CHECK_OP(Lt, <, val1, val2)
#define RTC_CHECK_GE(val1, val2) RTC_CHECK_OP(Ge, >=, val1, val2)
#define RTC_CHECK_GT(val1, val2) RTC_CHECK_OP(Gt, >, val1, val2)
// The RTC_DCHECK macro is equivalent to RTC_CHECK except that it only generates
// code in debug builds. It does reference the condition parameter in all cases,
// though, so callers won't risk getting warnings about unused variables.
#define RTC_DCHECK(condition) RTC_CHECK(condition)
#define RTC_DCHECK_EQ(v1, v2) RTC_CHECK_EQ(v1, v2)
#define RTC_DCHECK_NE(v1, v2) RTC_CHECK_NE(v1, v2)
#define RTC_DCHECK_LE(v1, v2) RTC_CHECK_LE(v1, v2)
#define RTC_DCHECK_LT(v1, v2) RTC_CHECK_LT(v1, v2)
#define RTC_DCHECK_GE(v1, v2) RTC_CHECK_GE(v1, v2)
#define RTC_DCHECK_GT(v1, v2) RTC_CHECK_GT(v1, v2)
#define RTC_DCHECK(condition) RTC_EAT_STREAM_PARAMETERS(condition)
// This is identical to LogMessageVoidify but in name.
class FatalMessageVoidify {
FatalMessageVoidify() { }
// This has to be an operator with a precedence lower than << but
// higher than ?:
void operator&(std::ostream&) { }
#define FATAL() rtc::FatalMessage(__FILE__, __LINE__).stream()
// TODO(ajm): Consider adding RTC_NOTIMPLEMENTED macro when
// base/logging.h and system_wrappers/logging.h are consolidated such that we
// can match the Chromium behavior.
// Like a stripped-down LogMessage from logging.h, except that it aborts.
class FatalMessage {
FatalMessage(const char* file, int line);
// Used for RTC_CHECK_EQ(), etc. Takes ownership of the given string.
FatalMessage(const char* file, int line, std::string* result);
NO_RETURN ~FatalMessage();
std::ostream& stream() { return stream_; }
void Init(const char* file, int line);
std::ostringstream stream_;
// Performs the integer division a/b and returns the result. CHECKs that the
// remainder is zero.
template <typename T>
inline T CheckedDivExact(T a, T b) {
RTC_CHECK_EQ(a % b, 0) << a << " is not evenly divisible by " << b;
return a / b;
} // namespace rtc
#else // __cplusplus not defined
// C version. Lacks many features compared to the C++ version, but usage
// guidelines are the same.
#define RTC_CHECK(condition) \
do { \
if (!(condition)) { \
rtc_FatalMessage(__FILE__, __LINE__, "CHECK failed: " #condition); \
} \
} while (0)
#define RTC_CHECK_EQ(a, b) RTC_CHECK((a) == (b))
#define RTC_CHECK_NE(a, b) RTC_CHECK((a) != (b))
#define RTC_CHECK_LE(a, b) RTC_CHECK((a) <= (b))
#define RTC_CHECK_LT(a, b) RTC_CHECK((a) < (b))
#define RTC_CHECK_GE(a, b) RTC_CHECK((a) >= (b))
#define RTC_CHECK_GT(a, b) RTC_CHECK((a) > (b))
#define RTC_DCHECK(condition) \
do { \
if (RTC_DCHECK_IS_ON && !(condition)) { \
rtc_FatalMessage(__FILE__, __LINE__, "DCHECK failed: " #condition); \
} \
} while (0)
#define RTC_DCHECK_EQ(a, b) RTC_DCHECK((a) == (b))
#define RTC_DCHECK_NE(a, b) RTC_DCHECK((a) != (b))
#define RTC_DCHECK_LE(a, b) RTC_DCHECK((a) <= (b))
#define RTC_DCHECK_LT(a, b) RTC_DCHECK((a) < (b))
#define RTC_DCHECK_GE(a, b) RTC_DCHECK((a) >= (b))
#define RTC_DCHECK_GT(a, b) RTC_DCHECK((a) > (b))
#endif // __cplusplus